| [GMCnet] Olds 455 Engine Oil Flow Path [message #211273] |
Sun, 16 June 2013 13:49  |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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G'day,
There has been much speculation regarding the recommendation not use the oil cooler in the radiator after an engine failure. It is
the intent of this email to review the engine oil flow path to form a consensus if that is correct or not.
This message was prepared by John Sharpe and myself.
Oil Flow Path in a 455 / 403 powered GMC Motorhome
Below is a picture of the inside of the oil cooler / filter adapter.
http://www.gmcmhphotos.com/photos/455-403-engine-oil-flow-path/p49551-oil-cooler-filter-ad.html
There are three “ports’ in the concave center section; from right to left they are:
1) oil entry port from the engine oil pump
2) oil cooler adapter mount and oil return to the engine
3) 5.3 to 6.3 psi bypass valve and return to engine
The distance from the center of the oil entry port to the center of the bypass valve is about 1 ¼ inches.
The oil flow path is as follows:
From the oil pump into the concave section of the oil cooler / filter adapter through the port on the right.
From the concave section of the oil cooler / filter adapter to the oil cooler adapter.
From the oil cooler adapter through a hose / tube to the oil cooler in the radiator.
Through the oil cooler in the radiator.
From the oil cooler in the radiator back through a hose / tube to the oil cooler adapter.
From the oil cooler adapter to the OD of the oil filter (outside the filter element).
From the OD of the oil filter to the ID of the oil filter (through the filter element).
From the oil filter into the engine through the center port in the oil filter adapter.
Below is a picture of the interface between the engine block and the oil cooler / filter adapter.
http://www.gmcmhphotos.com/photos/455-403-engine-oil-flow-path/p49548-block-oil-cooler-fil.html
Oil enters the oil cooler / filter adapter via the upper port and back into to the engine via the lower port. The lower port has two
feeds; one from the oil filter the second; the bypass valve.
Below is a picture of the oil cooler / filter adapter with the bypass valve removed. Note the “poppet guides” at 12:00 – 4:00 –
8:00. Using deep well sockets I measured the ID of those guides and found that they tapered inwards as the bore got deeper. At the
top the ID was 0.576 inches, in the middle the ID was 0.558 inches, and at the bottom it was 0.543 inches.
http://www.gmcmhphotos.com/photos/455-403-engine-oil-flow-path/p49549-bypass-poppet-removed.html
Below is a picture of the bypass valve seat, poppet, and spring.
http://www.gmcmhphotos.com/photos/455-403-engine-oil-flow-path/p49550-bypass-poppet.html
If you look closely at the poppet you will see one flat area (at about 2:00). The fit of the poppet in between the three guides left
a bit to be desired as it varied from 0.533 to 0.517 inches OD (where the flat spot was).
Below you will find the oil flow schematic and write up for the 455 / 403 engine as found in the Maintenance Manual (MM).
http://www.gmcmhphotos.com/photos/455-403-engine-oil-flow-path/p49554-engine-lubricating-system.html
MM write up below:
Oil enters the pump through a screened inlet located near the bottom rear of the oil pan. The pressurized oil from the pump passes
through the engine oil cooler located in the radiator tank then to the oil filter located on the right rear side of the engine
block, see Figure 2. The oil filter base has a by-pass valve which in the event of filter restriction will open at 5.3 to 6.3 psi.
It then enters the right gallery where it is distributed to the five main bearings. The right bank valve lifters receive oil from
this gallery from eight feed holes that intersect the gallery.
The line drawing below of the oil flow external to the engine can be found in the MM.
http://www.gmcmhphotos.com/photos/455-403-engine-oil-flow-path/p49555-external-oil-path.html
As a guesstimate the total length of the hoses to / from the engine is 9 feet.
The line drawing of the oil filter / cooler adapter / filter below can be found in the MM.
http://www.gmcmhphotos.com/photos/455-403-engine-oil-flow-path/p49558-oil-cooled-filter-adapter.html
As a guesstimate the oil cooler adapter is 1 1/4 inches tall.
Below is a picture of the screen in the oil pump pickup.
http://www.gmcmhphotos.com/photos/455-403-engine-oil-flow-path/p49557-oil-pump-intake-screen.html
Using a numbered drill we determined that the size of the “square holes” in the screen were 0.055 inches in width and height. With
the help of Pythagoras the corner to corner measurement of the “square holes” was calculated to be 0.077 inches. Therefore in theory
the largest size particle that can enter the oil pump is 0.077 inches. Yes, I realize a sliver that was less than that in width and
height could be longer, however it would have to pass through the screen lengthwise.
Given all the information above we believe the cold oil bypass flow path to be:
1) engine starter turns the engine / distributor / oil pump
2) oil is sucked through the screen and into the oil pump
3) oil is pumped into the concave area of the oil cooler / filter adapter
4) oil is thick and the pressure differential across the bypass valve exceeds 5.3 to 6.3 psi
5) the bypass valve opens and oil is returned to the engine
Why would the oil take the following flow path?
1) from the oil cooler / filter adapter to the oil cooler adapter
2) through 4 ½ feet of hose to the radiator cooler
3) through the radiator oil cooler
4) back through 4 ½ feet of hose
5) into the oil cooler adapter
6) Into the oil cooler / filter adapter
7) Through the bypass valve
Instead of the 1 ¼ inches from the inlet to the bypass valve in the concave area in the oil cooler / filter adapter!
Comments / observations please.
Now lets move on to the recommendation to cease use of the radiator oil cooler after an engine failure.
Below is a photograph of a failed piston:
http://www.gmcmhphotos.com/photos/455-403-engine-oil-flow-path/p49556-failed-piston.html
How much contamination would you guesstimate this failure generated? An ounce or two?
Let’s say that the owner of this GMC continued to drive the GMC and ignore the noise the engine made (he did not) and it lead to the
top of the piston fracturing. That would create another couple of ounces – MAYBE.
Let’s say the owner was a complete idiot (he is not) and kept driving until the bearing on the rod this piston was attached to
failed. That would add an ounce or so to the contamination.
I reckon as a worst case scenario you might get 6 ounces of contamination in the oil cooler from a catastrophic engine failure.
Comments / observations please.
Finally let’s discuss the cleaning of the radiator oil cooler.
Let’s say the engine failure puts 6 ounces of contamination into the oil pan. It has to get past the screen in the oil pump pickup
so the largest particles will be 0.0777 inches in size.
Let’s say that all 6 ounces makes it to the oil cooler in the radiator and should be cleaned out.
Someone suggested a pump setup that would pump a high flow of “cleaning solution” backwards through the oil cooler. That makes sense
to me. It should be setup so that you can capture the contamination after it is removed so the amount can be determined and the
makeup determined from a material stand point which would help determine where it came from.
Here’s the punch line – even if you don’t get all of the contamination out of the oil cooler the oil filter will catch it during
normal operation of the engine!
As noted previously engine oil is bypassed BEFORE it gets to the oil cooler / filter adapter meaning the contamination that is not
trapped by the filter can’t get into the engine!
Comments / observations please!
Regards,
Rob M.
Sydney, Australia
JohnS
Humble, Texas
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Olds 455 Engine Oil Flow Path [message #211283 is a reply to message #211273] |
Sun, 16 June 2013 15:36  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Everything you stated is in keeping with how I understood the path. Question is are all oil filters these days properly QCd as in end cap to element seal, and what is the design of the stock cooler A tank within a tank but I thought there was some sort of serpentine diverter in there to increase contact and surface area. Also known to hold on to debris and then release it at will. Need to know more about the cooler itself. If cooler can 'get' us then only defense is a top quality filter.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Olds 455 Engine Oil Flow Path [message #211326 is a reply to message #211273] |
Sun, 16 June 2013 22:53 |
Cadillackeeper
Messages: 464
Registered: October 2012
Location: Fort Lauderdale
Karma: 1
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Senior Member |
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Its kinda funny how you speak of driving with noise.My 500 swap in my car had Quite a few hiccups along the way.All sussed out for the past few years but.After the second rebuild from a cheap broken timing chain crank gear.I had a bang and then a few weeks later at certain rpm it would rod knock and then go away again, sometimes a day,sometimes an hour and sometimes weeks.Well I will link a photo.The rod,bearings
were obliterated.they left a chunk in the pan.It broke the rod cap and bent the ARP's
90 degrees.When the crank would hit what was left of the rod it would blast it up to the top and hence no noise.If the bent valves seated and it sparked it would throw it down to bash the crank.I drove for a few months until I finally did a compression check and found the open hole.Wait till you get to see this stuff.
77 455 Elaganza II and 67 Animal, Built 500 Powered Eldo
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| Re: [GMCnet] Olds 455 Engine Oil Flow Path [message #211331 is a reply to message #211273] |
Sun, 16 June 2013 23:30 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I received an email today from Dick Paterson today. He was in agreement with what I said. He further stated that he believed the confusion of some people might stand from the fact that there are 3 possible bypass paths in the Olds engine.
1. is the bypass at the oil pump to used prevent over pressurization.
2. is the bypass in the oil filter adapter that we are talking about here.
3. is the bypass located in some oil filters. Use of a bypass filter is not recommended on the Olds 455. Dick stated that if a bypass filter is used on a 455 that you could pass unfiltered oil out of the oil cooler to the engine.
Dick uses and recommends Wix 51258 on the Olds 455.
Whatever filter you choose to use, DO NOT USE A BYPASS FILTER. There is already a bypass located in the oil filter adapter so a bypass filter is unnecessarily.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Olds 455 Engine Oil Flow Path [message #212910 is a reply to message #212909] |
Mon, 01 July 2013 00:18 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Rob, Thanks to you and John for doing the research to prove what I thought was the normal oil flow. We also need to thank Dick Paterson for reenforcing what I thought.
We do need to stress that only recommended oil filters WITHOUT a built in bypass should be used in the GMC.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Olds 455 Engine Oil Flow Path [message #213050 is a reply to message #212955] |
Tue, 02 July 2013 16:00 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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| JohnL455 wrote on Mon, 01 July 2013 12:03 |
Isn't No 1 more of a blowoff/popoff and would have nothing to do with cooler parh junk?
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It is my belief that the pop off valve is located on the unfiltered side of the oil filter and when it opens near by crap can enter the engine . This crap likely passed from or thru the cooler before the pop off opened. So the cleaner the unfiltered side of the filter the better. Anyone that thinks fine crap( it has to pass thru the oil pump screen) can't move thru the cooler to the oil filter is taking a chance I wouldn't feel comfortable with.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: [GMCnet] Olds 455 Engine Oil Flow Path [message #213084 is a reply to message #213075] |
Tue, 02 July 2013 20:56 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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| Robert Mueller wrote on Tue, 02 July 2013 17:34 |
Roy,
Did you read the very first message in this thread? Did you look at the pictures?
Regards,
Rob M.
-----Original Message-----
From: roy@gmcnet.org
JohnL455 wrote on Mon, 01 July 2013 12:03
> Isn't No 1 more of a blowoff/popoff and would have nothing to do with cooler parh junk?
It is my belief that the pop off valve is located on the unfiltered side of the oil filter and when it opens near by crap can enter
the engine . This crap likely passed from or thru the cooler before the pop off opened. So the cleaner the unfiltered side of the
filter the better. Anyone that thinks fine crap( it has to pass thru the oil pump screen) can't move thru the cooler to the oil
filter is taking a chance I wouldn't feel comfortable with.
--
Roy
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I read it and as I see it the pop off valve will only open if the .pressure across the filter media is approximately 6 lbs or more at witch time the pop off will open and allow oil on the outer area of the filter to bypass the media and flow into the engine by way of the pop off valve think about it when the valve opens oil will flow thru it. That is as simple as I can explained it.
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Roy Keen
Minden,NV
76 X Glenbrook
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| Re: [GMCnet] Olds 455 Engine Oil Flow Path [message #213112 is a reply to message #213091] |
Wed, 03 July 2013 03:27 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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The only way for oil to get from the cooler to the engine is through the oil filter. The is no connection to allow oil flow out of the cooler to bypass the filter. It makes no difference whether the bypass valve is open or closed there is still no path for oil cooler oil to get to the engine without going through filter first.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Olds 455 Engine Oil Flow Path [message #213220 is a reply to message #213155] |
Wed, 03 July 2013 20:24 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| bdub wrote on Wed, 03 July 2013 14:05 |
I imagine James Harper, in Gladewater, TX, has one he'll loan you if he
hasn't already thrown it away. He advocates not using it since cars don't and it only introduces more components to fail.
bdub
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Bdub and any body else that will listen.
Before the coach, I have owned 3 street cars with lube oil coolers external to the engine. I was forced to add a lube oil cooler to a fourth (not a stock configuration).
Just about every marine adaptation of a passcar motor has an external lube oil cooler. AND they are rated at lower horsepower than the passcar version. Do You Believe there might be a reason.
Please leave the oil cooler on your coach. If you choose to remove it, install a lube oil temperature gauge. Then, never run with LOT above 270°F. Why? Because if that is what you are seeing some places are hotter and when dyno oil reaches 305°F that molecule ceases to be lubricating oil - Right Then.... this is not a time/temperature game.
If anybody that ever owned a 442 tried to load the engine like we can any time we meet a hill, he would be in jail (if he survived at all).
Matt - in the comfort of my dinette waiting for the fireworks
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Olds 455 Engine Oil Flow Path [message #213238 is a reply to message #211273] |
Wed, 03 July 2013 22:57 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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I was talking about the pump relief as a Popoff. The 455 oil filter bypass is another 2nd story. ( And the filter itself if you were to use that type as a 3rd). The way I understand it this pump popoff relief is in the event some moron were to start a sub zero engine with 50 weight oil and rev it to 3500 RPM this would save the pump drive gears.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Olds 455 Engine Oil Flow Path [message #213252 is a reply to message #213238] |
Thu, 04 July 2013 02:17 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I for one misunderstood what you were talking about. That valve at the pump establishes the maximum pressure that can be reached by the the pump. It bleeds off some oil directly back to the pan to release some of the pressure in the pump.
Thanks for explaining again what you were referring to. I misunderstood the first time around.
Note: this pressure relief valve at the oil pump has nothing to do with changing the route of oil that has run through cooler.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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